Goals: Mariner 1 was the first attempt by the United States to send a spacecraft to Venus. It was to fly by the planet at a distance of about 29,000 km (about 18,000 miles), transmitting a variety of scientific data but no pictures.

Accomplishments: None. A problem with the guidance system shortly after launch made steering impossible and directed the spacecraft toward a crash, possibly in North Atlantic shipping lanes or in an inhabited area. The Range Safety Officer issued a destruct command about 5 minutes after launch, just 6 seconds before the spacecraft would have separated from its booster, after which the launch vehicle could not have been destroyed.